CN110170528B - Control method for white spot defect on surface of cold-rolled low-carbon steel - Google Patents

Control method for white spot defect on surface of cold-rolled low-carbon steel Download PDF

Info

Publication number
CN110170528B
CN110170528B CN201910334459.8A CN201910334459A CN110170528B CN 110170528 B CN110170528 B CN 110170528B CN 201910334459 A CN201910334459 A CN 201910334459A CN 110170528 B CN110170528 B CN 110170528B
Authority
CN
China
Prior art keywords
rolling
temperature
dephosphorization
equal
acid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201910334459.8A
Other languages
Chinese (zh)
Other versions
CN110170528A (en
Inventor
许斌
吕超杰
于晓飞
程迪
王田惠
程帅
王风强
苏振军
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Handan Iron and Steel Group Co Ltd
HBIS Co Ltd Handan Branch
Original Assignee
Handan Iron and Steel Group Co Ltd
HBIS Co Ltd Handan Branch
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Handan Iron and Steel Group Co Ltd, HBIS Co Ltd Handan Branch filed Critical Handan Iron and Steel Group Co Ltd
Priority to CN201910334459.8A priority Critical patent/CN110170528B/en
Publication of CN110170528A publication Critical patent/CN110170528A/en
Application granted granted Critical
Publication of CN110170528B publication Critical patent/CN110170528B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
    • B21B1/463—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a continuous process, i.e. the cast not being cut before rolling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
    • B21B45/0269—Cleaning
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B45/04—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing
    • B21B45/06—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing of strip material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B45/04—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing
    • B21B45/08—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing hydraulically

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Metal Rolling (AREA)

Abstract

The invention relates to a cold-rolled low-carbon steel surface white spot defect control method, and belongs to the technical field of metallurgical plate production. The route comprises the working procedures of continuous casting, hot rolling, acid rolling and continuous annealing; ensuring H in a hot rolling heating furnace in the hot rolling procedure2S≤120mg/Nm3The rough rolling dephosphorization pass is more than or equal to 3 times, the water temperature of pre-dephosphorization, rough rolling dephosphorization, finish rolling dephosphorization and laminar cooling is less than or equal to 40 ℃, the temperature of a finish rolling inlet is less than or equal to 1100 ℃, the laminar cooling adopts a front-section cooling mode of starting cooling from the beginning end of a cooling area, the finish rolling temperature is 800-; the temperature of the hot coil on the line of the acid rolling process is less than or equal to 80 ℃, the temperature control range of the acid liquor is 70-100 ℃, the acid concentration control range is 30-190g/L, and the acid washing belt speed is less than or equal to 200 m/min; the elongation percentage of the withdrawal and straightening machine is 1.5-3.0%. The invention can effectively avoid or reduce the defects of various surface white spots of the cold-rolled low-carbon strip steel.

Description

Control method for white spot defect on surface of cold-rolled low-carbon steel
Technical Field
The invention relates to a cold-rolled low-carbon steel surface white spot defect control method, and belongs to the technical field of metallurgical plate production.
Background
The surface quality of the strip steel is an important embodiment of the quality of strip steel products; the cold rolling low carbon steel production has long process flow, and the defect appearance evolves when passing through different processes, so that the surface defect types of the final product are diversified and complicated; meanwhile, the appearance characteristics of different defects to the final work order are very similar, which brings great difficulty to the work of surface quality, so that only a few enterprises can stably produce cold-rolled automobile plates with excellent surface quality in the national range, especially automobile outer plates, and the overall qualification rate is at a lower level. The white spot defect on the surface of the cold-rolled plate is a common degradation defect, the macroscopic morphology is white or light white, and the macroscopic morphology presents different morphological characteristics of a point shape, a linear shape, a mountain water shape, a willow leaf shape, a strip shape, an oval shape and the like. The steel strip surface damage, foreign matters such as iron scales and other residues are pressed into the surface of the steel strip under the influence of multiple factors such as dephosphorization, roll and roller way control, process temperature control in the hot rolling process, acid pickling effect and rubber roll state in the cold rolling process, and the like, and after continuous annealing, the steel strip presents different color characteristics and form differences from the normal surface of the steel strip, and can be expressed as white spot defects. At present, the research on white spot defects in various domestic steel mills and scientific research institutes mainly focuses on the aspects of hot rolling process temperature control, roll system maintenance and the like, or only conducts experimental analysis and mechanism discussion, or only aims at the iron scale control of hot rolled strip steel.
The paper 'cold-rolled substrate iron scale press-in defect control measures' only explains a plurality of common hot-rolled iron scales caused by slab heating temperature, dephosphorization pressure and roller problems by combining actual production experience, does not relate to specific process parameters, and does not reflect white spot defects caused by insufficient control of an acid rolling process.
The paper 'influence of hot rolling process parameters and oxygen supply difference on the structure and thickness of the iron scale' researches the influence rule of different process parameters on the iron scale, but the process points are few, and the content related to the aspect of production line equipment is insufficient.
The application number 201610127232.2 discloses a hot rolling control method for iron scale at the edge of low-carbon aluminum killed steel, which solves the problem that the iron scale at the edge of strip steel is not easy to be washed cleanly by acid in the prior art, can effectively avoid the white spot defect caused by the willow-leaf-shaped secondary iron scale, is only suitable for the production of aluminum killed steel, and does not relate to key control points such as cooling water temperature, hot-coil cooling mode and acid washing process.
The Chinese patent with the application number of 201810387617.1 discloses a processing method of a low-carbon aluminum killed steel acid-pickled plate, wherein the acid-pickled plate is formed by a plate blank through the steps of heating, rough rolling, finish rolling, cooling, coiling and acid pickling, can effectively avoid the defect of landscape-shaped white spots, and is only suitable for the production of the acid-pickled plate.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a control method for the white spot defect on the surface of the cold-rolled low-carbon steel, which can effectively avoid or reduce various white spot defects on the surface of the cold-rolled low-carbon strip steel, improve the surface quality of a finished strip steel product and improve the production yield.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a cold rolling low carbon steel surface white spot defect control method, the route is the process of continuous casting, hot rolling, acid rolling and continuous annealing; ensuring H in a hot rolling heating furnace in the hot rolling procedure2S≤120mg/Nm3The rough rolling dephosphorization pass is more than or equal to 3 times, the water temperature of pre-dephosphorization, rough rolling dephosphorization, finish rolling dephosphorization and laminar cooling is less than or equal to 40 ℃, the temperature of a finish rolling inlet is less than or equal to 1100 ℃, the laminar cooling adopts a front-section cooling mode of starting cooling from the beginning end of a cooling area, the finish rolling temperature is 800-;
the temperature of the hot coil on the line of the acid rolling process is less than or equal to 80 ℃, the temperature control range of the acid liquor is 70-100 ℃, the acid concentration control range is 30-190g/L, and the acid washing belt speed is less than or equal to 200 m/min; the elongation percentage of the withdrawal and straightening machine is 1.5-3.0%.
In the hot rolling procedure, the time of single-layer stacking and fan cooling after coiling is not less than 48 hours, so that the coiling temperature of the online hot coil in the acid rolling procedure is not more than 80 ℃.
In the hot rolling process, the temperature of a casting blank out of a heating furnace is 1100-1300 ℃, the water pressure of a pre-dephosphorization, rough-rolling dephosphorization and finish-rolling dephosphorization system is more than or equal to 190bar, and a high-speed steel roller with a roller gap lubricating device is used for the F1-F5 frame roller; and precisely controlling the threading speed of finish rolling F7 to be more than or equal to 9.5 m/s.
In the hot rolling procedure, the wear depth of a guide plate at a finish rolling and coiling inlet does not exceed 5mm, and no nodulation and weld repair residues exist; the full-line roller way runs well, the guide rollers are not allowed to be blocked, the total number of free rollers of the roller way cannot exceed 3, and two or more continuous free rollers are not allowed;
in the acid rolling process, the head and tail cutting amount of an acid washing inlet is more than or equal to 4.8 m.
In the hot rolling process, the finish rolling comprises a 7-stand finish rolling mill from F1 to F7.
Theoretical analysis:
the method ensures that the iron scale on the surface of the strip steel is fully dephosphorized in a multi-pass and high-pressure environment in the hot rolling process by controlling the minimum times of the dephosphorization passes and limiting the minimum value of the dephosphorization water pressure, ensures the dephosphorization effect and avoids the generation of punctiform and willow-leaf-shaped white spot defects; by controlling the temperature of the casting blank out of the heating furnace, lower H is combined2S content, molten Fe during casting blank discharge2SiO4Content, surface color difference and landscape type white spots caused by the increase of the adhesiveness of the primary scale are avoided; the method has the advantages of low finish rolling temperature, low coiling temperature, use of a front-section cooling mode of starting cooling at the beginning end of a cooling area, single-layer stacking and fan cooling, application of process control points such as a high-speed steel roller and the like, avoidance of increase of the thickness of an iron scale layer caused by high temperature of strip steel, reduction of Fe with high brittleness2O3The content of the iron oxide scale is increased, the stability of the iron oxide scale in the rolling process is improved, and the defect of strip-shaped white spots generated by pressing caused by cracking is avoided; the guide plate has abrasion depth, roller bed foreign bodies and guide rollers operate normally and the likeThe control in the aspect can avoid the generation of strip-shaped and linear white spots caused by surface damage due to the relative motion of the strip steel, the production line guide plate and the guide roller; the method has the advantages that the hot coil temperature on the acid rolling line is controlled, the temperature and the concentration of acid liquor are improved, the pickling speed is reduced, the elongation of the tension leveler is improved, the pickling quality in the pickling process is improved, and the elliptical white spot defect caused by degumming of the rubber roll due to overhigh coil temperature is avoided.
Drawings
FIG. 1 shows the surface topography of a cold-rolled steel strip corresponding to example 1;
FIG. 2 shows the surface topography of the cold-rolled strip steel corresponding to example 2;
FIG. 3 shows the surface topography of the cold-rolled steel strip corresponding to example 3;
FIG. 4 shows the surface topography of the cold-rolled steel strip corresponding to example 4;
FIG. 5 shows the surface topography of the cold-rolled steel strip corresponding to example 5;
FIG. 6 shows the surface topography of the cold-rolled steel strip corresponding to example 6;
FIG. 7 shows the surface topography of the cold-rolled steel strip corresponding to example 7.
Detailed Description
The present invention will be described in further detail with reference to specific examples.
The invention provides a method for controlling white spot defects on the surface of cold-rolled low-carbon steel, which comprises the working procedures of continuous casting, hot rolling, acid rolling and continuous annealing.
Example 1:
h in the atmosphere of the heating furnace is controlled in the hot rolling procedure2The S content is required to be controlled to be 120mg/Nm3The temperature of the casting blank taken out of the heating furnace is 1280 ℃, the temperature of the pre-dephosphorization water is 40 ℃, and the pressure of the pre-dephosphorization water is 201 bar; the rough rolling dephosphorization pass is 3 times, the rough rolling dephosphorization water temperature is 40 ℃, and the rough rolling dephosphorization water pressure is 200 bar; the inlet temperature of finish rolling is 1080 ℃, and the maximum abrasion depth of a guide plate at the inlet of the finish rolling is 4.7 mm. Checking that no nodules and repair welding residues exist, enabling the full-line roller way to run normally, and enabling the guide roller to run without blockage; the temperature of the fine rolling dephosphorization water is 40 ℃, and the pressure of the fine rolling dephosphorization water is 199 bar; finish rolling is carried out by using a finish rolling machine with 7 frames including F1-F7, wherein the rolls of the finish rolling machine with F1-F5 are cast by using high-speed steel rolls with roll gap lubricating equipment; the threading speed of the F7 finishing mill is 10.5 m/s; final (a Chinese character of 'gan')The rolling temperature is 938 ℃, laminar cooling adopts a front-section cooling mode that the starting end of a cooling area starts to be cooled, the coiling temperature is 700 ℃, and the coiled material is completely placed into a warehouse area for single-layer stacking and cooled by a fan for 68 hours;
in the acid rolling process, the temperature of an upper line hot coil is 66 ℃, the head and tail cutting amount of an acid washing inlet is 5m, the elongation of a tension leveler is 2.2%, the actual control value of the acid liquor temperature is 80 ℃, the actual control value of the acid concentration is 54g/L, and the maximum acid washing speed is 160 m/min.
Through the production of the embodiment, the spot-shaped white spots on the plate surface are obviously reduced and approximate to sporadic white spot-shaped white spots, and as shown in figure 1, the white spot defect is obviously improved.
Example 2:
h in the atmosphere of the heating furnace is controlled in the hot rolling procedure2The S content is required to be controlled at 100mg/Nm3The temperature of the casting blank out of the heating furnace is 1168 ℃, the temperature of the pre-dephosphorization water is 36 ℃, and the pressure of the pre-dephosphorization water is 193 bar; the rough rolling dephosphorization pass is 5 times, the rough rolling dephosphorization water temperature is 36 ℃, and the rough rolling dephosphorization water pressure is 194 bar; the inlet temperature of finish rolling is 1100 ℃, the maximum abrasion depth of a guide plate at the inlet of finish rolling is 4.7mm, no nodules and repair welding residues are detected, the operation of a full-line roller way is normal, and a guide roller does not have blockage during operation; the temperature of the fine rolling dephosphorization water is 37 ℃, and the pressure of the fine rolling dephosphorization water is 194 bar. Finish rolling is carried out by using a finish rolling machine with 7 frames including F1-F7, wherein the rolls of the finish rolling machine with F1-F5 are cast by using high-speed steel rolls with roll gap lubricating equipment; the threading speed of an F7 finishing mill is 10.9m/s, the finishing temperature is 950 ℃, the laminar cooling adopts a front-section cooling mode that the starting end of a cooling area starts to be cooled, the coiling temperature is 710 ℃, and the coiled strip is completely placed into a warehouse area for single-layer stacking and is cooled by a fan for 68 hours;
in the acid rolling process, the temperature of the hot coil on line is 63 ℃, the head and tail cutting amount at the acid washing inlet is 5m, the elongation of the tension leveler is 1.9%, the actual control value of the acid liquor temperature is 83 ℃, the actual control value of the acid concentration is 58g/L, and the maximum acid washing speed is 173 m/min.
By the production of this example, as shown in FIG. 2, no white spot defect was generated.
Example 3:
h in the atmosphere of the heating furnace is controlled in the hot rolling procedure2The S content is required to be controlled at 100mg/Nm3The temperature of the casting blank out of the heating furnace is 1168 ℃, and dephosphorization water is removed in advanceThe water temperature is 36 ℃, and the pre-dephosphorization water pressure is 193 bar; the rough rolling dephosphorization pass is 5 times, the rough rolling dephosphorization water temperature is 36 ℃, and the rough rolling dephosphorization water pressure is 194 bar; the inlet temperature of finish rolling is 1050 ℃, and the maximum abrasion depth of a guide plate at the inlet of finish rolling is 5 mm; checking that no nodules and repair welding residues exist, enabling the full-line roller way to run normally, and enabling the guide roller to run without blockage; the temperature of the fine rolling dephosphorization water is 37 ℃, and the pressure of the fine rolling dephosphorization water is 194 bar; finish rolling is carried out by using a finish rolling machine with 7 frames including F1-F7, wherein the rolls of the finish rolling machine with F1-F5 are cast by using high-speed steel rolls with roll gap lubricating equipment; the threading speed of an F7 finishing mill is 10.9m/s, the finishing temperature is 800 ℃, the laminar cooling adopts a front-section cooling mode that the starting end of a cooling area starts to be cooled, the coiling temperature is 710 ℃, and the coiled strip is completely placed into a warehouse area for single-layer stacking and is cooled by a fan for 68 hours;
in the acid rolling process, the temperature of the hot coil on line is 63 ℃, the head and tail cutting amount of an acid washing inlet is 4.8m, the elongation of a tension leveler is 1.9%, the actual control value of the acid liquor temperature is 83 ℃, the actual control value of the acid concentration is 58g/L, and the maximum acid washing speed is 173 m/min;
by the production of this example, as shown in FIG. 3, no white spot defect was generated.
Example 4:
h in the atmosphere of the heating furnace is controlled in the hot rolling procedure2The S content is required to be controlled at 90mg/Nm3The temperature of the casting blank out of the heating furnace is 1100 ℃, the temperature of the pre-dephosphorization water is 32 ℃, and the pressure of the pre-dephosphorization water is 196 bar; the rough rolling dephosphorization pass is 5 times, the water temperature of rough rolling dephosphorization water is 32 ℃, and the pressure of the rough rolling dephosphorization water is 194 bar; the inlet temperature of finish rolling is 1042 ℃, and the maximum abrasion depth of a guide plate at the inlet of the finish rolling is 3.0 mm; checking that no nodules and repair welding residues exist, enabling the full-line roller way to run normally, and enabling the guide roller to run without blockage; the water temperature of the fine rolling phosphorus water is 32 ℃, and the pressure of the fine rolling phosphorus removal water is 194 bar; finish rolling is carried out by using a finish rolling machine with 7 frames including F1-F7, wherein the rolls of the finish rolling machine with F1-F5 are cast by using high-speed steel rolls with roll gap lubricating equipment; the threading speed of the F7 finishing mill is 10.9 m/s. The finishing temperature is 887 ℃, the laminar cooling adopts a front-section cooling mode that the starting end of a cooling area starts to be cooled, the coiling temperature is 750 ℃, and the coiled material is completely placed into a single-layer stack of a warehouse area and cooled by a fan for 48 hours;
in the acid rolling process, the temperature of the hot coil on line is 59 ℃, the head and tail cutting amount of an acid washing inlet is 5.2m, the elongation of the tension leveler is 1.9%, the actual control value of the acid liquor temperature is 83 ℃, the actual control value of the acid concentration is 58g/L, and the maximum acid washing speed is 173 m/min.
By the production of this example, as shown in FIG. 4, no white spot defect was generated.
Example 5:
h in the atmosphere of the heating furnace is controlled in the hot rolling procedure2The S content is required to be controlled at 77mg/Nm3The temperature of the casting blank out of the heating furnace is 1280 ℃, the temperature of the pre-dephosphorization water is 36 ℃, and the pressure of the pre-dephosphorization water is 201 bar; the rough rolling dephosphorization pass is carried out for 5 times, the water temperature of rough rolling dephosphorization water is 36 ℃, and the pressure of the rough rolling dephosphorization water is 200 bar; the inlet temperature of finish rolling is 1100 ℃, and the maximum abrasion depth of a guide plate at the inlet of finish rolling is 4.7 mm; checking that no nodules and repair welding residues exist, enabling the full-line roller way to run normally, and enabling the guide roller to run without blockage; the water temperature of the fine rolling phosphorus water is 36 ℃, and the pressure of the fine rolling phosphorus removal water is 199 bar; finish rolling is carried out by using a finish rolling machine with 7 frames including F1-F7, wherein the rolls of the finish rolling machine with F1-F5 are cast by using high-speed steel rolls with roll gap lubricating equipment; the threading speed of an F7 finishing mill is 11m/s, the finishing temperature is 910 ℃, the laminar cooling adopts a front-section cooling mode that the starting end of a cooling area starts to be cooled, the coiling temperature is 707 ℃, and the coiled strip is completely placed into a warehouse area for single-layer stacking and cooled by a fan for 72 hours;
in the acid rolling process, the temperature of the hot coil on line is 43 ℃, the head and tail cutting amount at the acid washing inlet is 5m, the elongation of the tension leveler is 3.0%, the actual control value of the acid liquor temperature is 100 ℃, the actual control value of the acid concentration is 190g/L, and the maximum acid washing speed is 143 m/min.
By the production of this example, as shown in FIG. 5, no white spot defect was generated.
Example 6:
h in the atmosphere of the heating furnace is controlled in the hot rolling procedure2The S content is required to be controlled at 77mg/Nm3The temperature of the casting blank out of the heating furnace is 1280 ℃, the temperature of the pre-dephosphorization water is 36 ℃, and the pressure of the pre-dephosphorization water is 201 bar; the rough rolling dephosphorization pass is carried out for 5 times, the water temperature of rough rolling dephosphorization water is 36 ℃, and the pressure of the rough rolling dephosphorization water is 200 bar; the inlet temperature of finish rolling is 1100 ℃, and the maximum abrasion depth of a guide plate at the inlet of finish rolling is 4.7 mm; checking that no nodules and repair welding residues exist, enabling the full-line roller way to run normally, and enabling the guide roller to run without blockage; the water temperature of the fine rolling phosphorus water is 36 ℃, and the pressure of the fine rolling phosphorus removal water is 199 bar; finish rolling with a 7-stand finish rolling mill F1-F7, wherein F1And (4) throwing the high-speed steel roll with the roll gap lubricating device on the roll of the F5 finishing mill. The threading speed of an F7 finishing mill is 11 m/s; the finishing temperature is 910 ℃, the laminar cooling adopts a front-section cooling mode that the starting end of a cooling area starts to be cooled, the coiling temperature is 707 ℃, and the coiled material is completely put into a single-layer stack of a reservoir area and cooled by a fan for 72 hours;
in the cold rolling procedure, the coiling temperature of the hot coil on line is 80 ℃, the head and tail cutting amount at the pickling inlet is 4.8m, the elongation of the tension leveler is 1.5%, the actual control value of the acid liquid temperature is 70 ℃, the actual control value of the acid concentration is 30g/L, and the maximum pickling speed is 200 m/min.
By the production of this example, as shown in FIG. 6, no white spot defect was generated.
Example 7:
h in the atmosphere of the heating furnace is controlled in the hot rolling procedure2The S content is required to be controlled to be 87mg/Nm3The temperature of the casting blank taken out of the heating furnace is 1300 ℃, the temperature of the pre-dephosphorization water is 34 ℃, and the pressure of the pre-dephosphorization water is 190 bar; the rough rolling dephosphorization pass is carried out for 5 times, the water temperature of rough rolling dephosphorization water is 35 ℃, and the pressure of the rough rolling dephosphorization water is 190 bar; the temperature of a finish rolling inlet is 1055 ℃, and the maximum abrasion depth of a guide plate at the finish rolling inlet is 3.0 mm; checking that no nodules and repair welding residues exist, enabling the full-line roller way to run normally, and enabling the guide roller to run without blockage; the temperature of the fine rolling dephosphorization water is 35 ℃, and the pressure of the fine rolling dephosphorization water is 190 bar; finish rolling is carried out on a 7-frame finishing mill with F1-F7, wherein the rolls of the F1-F5 finishing mill are cast with high-speed steel rolls with roll gap lubricating function; the threading speed of an F7 finishing mill is 9.5m/s, the finishing temperature is 887 ℃, the laminar cooling adopts a front-section cooling mode that the starting end of a cooling area starts to be cooled, the coiling temperature is 600 ℃, and the coiled strip is completely placed into a warehouse area for single-layer stacking and is cooled by a fan for 50 hours;
in the acid rolling process, the temperature of the hot coil on line is 71 ℃, the head and tail cutting amount of an acid washing inlet is 5.2m, the elongation of the tension leveler is 1.9%, the actual control value of the acid liquor temperature is 83 ℃, the actual control value of the acid concentration is 58g/L, and the maximum acid washing speed is 173 m/min.
By the production of this example, as shown in FIG. 7, no white spot defect was generated.

Claims (3)

1. A method for controlling white spot defects on the surface of cold-rolled low-carbon steel comprises the following steps of continuous casting, hot rolling, acid rolling and continuous rollingWithdrawing the working procedure; the method is characterized in that: in the hot rolling procedure, H in a hot rolling heating furnace is ensured2S≤120mg/Nm3The temperature of the casting blank out of the heating furnace is 1100-1168 ℃, the rough rolling dephosphorization pass is more than or equal to 3 times, the water temperature of the pre-dephosphorization, the rough rolling dephosphorization, the finish rolling dephosphorization and the laminar cooling is less than or equal to 40 ℃, the water pressure of the pre-dephosphorization, the rough rolling dephosphorization and the finish rolling dephosphorization systems is more than or equal to 190bar, and the high-speed steel roll with the roll gap lubricating equipment is used for the F1-F5 frame roll; accurately controlling the strip threading speed of finish rolling F7 to be more than or equal to 9.5m/s, the temperature of a finish rolling inlet to be less than or equal to 1100 ℃, adopting a front-section cooling mode of starting cooling from the beginning end of a cooling area for laminar cooling, wherein the finish rolling temperature is 800-; the abrasion depth of a guide plate at a coiling inlet is not more than 5mm, and no accretion or welding repair residues exist; the full-line roller way runs well, the guide rollers are not allowed to be blocked, the total number of free rollers of the roller way cannot exceed 3, and two or more continuous free rollers are not allowed;
the temperature of the hot coil on the line of the acid rolling process is less than or equal to 80 ℃, the temperature control range of the acid liquor is 70-100 ℃, the acid concentration control range is 30-190g/L, and the acid washing belt speed is less than or equal to 200 m/min; the elongation percentage of the withdrawal and straightening machine is 1.5-3.0%.
2. The method for controlling the white spot defect on the surface of the cold-rolled low-carbon steel as claimed in claim 1, wherein the method comprises the following steps: in the hot rolling procedure, the head and tail cutting amount of the pickling inlet is more than or equal to 4.8m in the acid rolling procedure.
3. The method for controlling the white spot defect on the surface of the cold-rolled low-carbon steel as claimed in claim 1 or 2, wherein: in the hot rolling procedure, the finish rolling comprises a 7-stand finish rolling mill from F1 to F7.
CN201910334459.8A 2019-04-24 2019-04-24 Control method for white spot defect on surface of cold-rolled low-carbon steel Active CN110170528B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910334459.8A CN110170528B (en) 2019-04-24 2019-04-24 Control method for white spot defect on surface of cold-rolled low-carbon steel

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910334459.8A CN110170528B (en) 2019-04-24 2019-04-24 Control method for white spot defect on surface of cold-rolled low-carbon steel

Publications (2)

Publication Number Publication Date
CN110170528A CN110170528A (en) 2019-08-27
CN110170528B true CN110170528B (en) 2021-05-04

Family

ID=67689983

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910334459.8A Active CN110170528B (en) 2019-04-24 2019-04-24 Control method for white spot defect on surface of cold-rolled low-carbon steel

Country Status (1)

Country Link
CN (1) CN110170528B (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112588844A (en) * 2020-10-28 2021-04-02 邯郸钢铁集团有限责任公司 Method for controlling iron scale of high-temperature hot coil of automobile O5 plate at large cooling rate
CN113263051A (en) * 2021-04-16 2021-08-17 首钢集团有限公司 Method for reducing press-in defects of iron sheet on surface of B-carbon-containing structural steel pickling plate
CN113578977A (en) * 2021-07-21 2021-11-02 张家港扬子江冷轧板有限公司 Method for eliminating press-in defect of high-strength automobile steel point-like foreign matter
CN114669595B (en) * 2022-03-28 2024-04-30 包头钢铁（集团）有限责任公司 Control method for pressing-in of salix-leaf-shaped iron oxide scale of hot-rolled low-carbon strip steel
CN115044833B (en) * 2022-06-13 2023-09-15 首钢集团有限公司 High-surface-quality 65Mn cold-rolled sheet and manufacturing method thereof

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6543122B1 (en) * 2001-09-21 2003-04-08 Alcoa Inc. Process for producing thick sheet from direct chill cast cold rolled aluminum alloy
CN104831207A (en) * 2015-04-16 2015-08-12 河北钢铁股份有限公司邯郸分公司 Thin gauge 600MPa grade hot galvanized plate production method
CN106086348A (en) * 2016-07-27 2016-11-09 唐山钢铁集团有限责任公司 A kind of cold rolling bailing band of high-strength high-elongation ratio and manufacture method thereof
CN108359908A (en) * 2018-04-04 2018-08-03 本钢板材股份有限公司 A kind of cold-rolled biphase steel and preparation method thereof
CN109468554B (en) * 2018-11-19 2020-12-01 广西柳州银海铝业股份有限公司 Method for eliminating white spot of cold-rolled aluminum coil edge annealing
CN109371208A (en) * 2018-11-27 2019-02-22 张家港浦项不锈钢有限公司 A kind of cold annealing and pickling technique of 1.5-2.0mm thickness 204Cu stainless steel

Also Published As

Publication number Publication date
CN110170528A (en) 2019-08-27

Similar Documents

Publication Publication Date Title
CN110170528B (en) Control method for white spot defect on surface of cold-rolled low-carbon steel
CN104826872B (en) A kind of controlled rolling method eliminating Surfaces of Hot Rolled Strip chromatic aberration defect
CN102921750B (en) Method for removing bright trace on surface of strip steel
CN108265227B (en) High-precision ultrathin cold-rolled steel strip for electronic components and production method thereof
CN108067507B (en) Control method for rough rolling warping of hot-rolled variety steel
CN111097798A (en) Stable production method of hot-rolled thin-specification ultrahigh-strength quenched ductile steel
CN107052060A (en) A kind of method for eliminating acid-cleaning plate Pinhole-shaped pit defect
CN107649522A (en) Surface quality of hot rolled steel coils control method
CN112692061A (en) Hot rolling method for improving surface quality of steel plate
CN111282993A (en) Near-net shape rail blank short-flow continuous casting and rolling production method and system
CN109201758B (en) ESP endless rolling intermediate finishing mill group and rolling method
CN104399748B (en) A kind of production technology that can replace conventional broadband steel hot continuous rolling
CN109226260B (en) Method for avoiding ultra-low carbon steel edge burr defect
CN107252821A (en) A kind of hot-rolled structural steel production method that can avoid producing the black steel defect of pickling
CN101524706A (en) Method for rolling low-carbon high-manganese steel continuously-cast blank in one heat
WO2023138121A1 (en) Method for producing thin specification steel plate
CN104998917A (en) Method for removing streak defects on hot rolled steel plate surface
CN115716086A (en) Hot-rolled ultrathin strip steel endless continuous casting and rolling production unit and production method thereof
CN114406000A (en) Continuous casting and rolling method for common low-carbon steel medium plate
CN112355051A (en) Rolling method of high-surface-quality marine steel plate
CN114054515A (en) Method for controlling cold rolling base material iron scale after rolling
CN101147919B (en) Method for reducing cold rolled galvanized plate surface defect with CSP hot rolled coil as raw material
CN112453055B (en) Method for controlling edge quality of interstitial-free IF steel and IF steel
CN112207130B (en) Combined oil scraping device for high-speed production of rolling mill
CN109604353A (en) The method for solving hot rolling acid-cleaning plate scenery with hills and waters line chromatic aberration defect

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant